Large numbers of containers are used to ship goods on a worldwide basis. Container shipping creates issues relating to both supply chain management and security. For a supply chain manager, having instant access to information that identifies a container's whereabouts is important for both inventory management and predicting customer delivery. Container security is obviously important from the standpoint of knowing whether or when security is breached.
Shipping containers are manufactured according to international standards that have encouraged generically designed containers that can be carried by ships, handled at international ports, and easily transferred to truck or rail. Container doors are typically sealed for security purposes. However, it is relatively easy to breach container security by either cutting the door seal; bypassing the seal entirely by cutting or removing door hasp structure; or by simply cutting a hole through the side of the container with a cutting torch.
Because of the sheer volume of containers in use today, it is not practical to physically inspect each one as they cross borders or change hands from one shipper to the next. It is estimated that only 2 to 30% of containers are physically inspected when they enter the United States, for example.
Container security is obviously a problem before entry into the United States in the first place. However, once inside the United States, containers are often temporarily stored in various transit locations where they can be accessed and broken into (transit centers, railyards, etc.). All of these various factors create an ongoing situation where a security breach is often not identified or recognized until the container reaches the destination where it is supposed to be unloaded.
It is presently not possible to prevent unauthorized entry into a container. However, knowing whether a container has been entered (whether entry is authorized or unauthorized), when it was entered, and where, is useful information to a shipper, over and above simply keeping track of the container's location on an ongoing basis. The system described here provides a different arrangement of components for providing the means to monitor container security along these lines.
The replacement costs for bolt-type seal locks is an ongoing issue for those shippers who handle large numbers of containers. Leaving aside the ongoing expense of cutting and discarding bolt-type seal locks when a container reaches its final destination, there are many legitimate reasons why the bolts need to be cut at an earlier point in time, for temporary entry into the container, due to customs inspections or other supply chain reasons. Therefore, in addition to describing an overall security system, what also follows below an improved design for the mechanical aspects of the locking structure in the seal lock—that enables bolt-type locks to be cut and reused or recycled at the place where they are cut.